VMWare is giving away their VMware Server product.
Even tho it says Beta, I have been told it is the a new release of the "old faithful" VMware software.
I have wanted to mess around with Virtual Machines, but there was no free product on the market. You can set up virtual machines, and test software, without worrying about infecting your machine, you just delete the virtual machine you created. You can browse the Internet with a virtual machine and not worry about malware or infection.
VMWare has virtual machines already created, that you can just download.
If your like me, and know nothing about it, don't just install it, and hope it works, research what it does and how it works first, if you decide to try it.
Have to fill out a form to receive a key to activate it.
Has Windows and Linux downloads.
http://www.vmware.com/download/server/
only those who will 
Don;t know much about VMWare, think it's spose to let you run an OS on your comp without installing it, but allowing it HDD access - unno.
But I think PC-BSD now supports it for those that want to try it that way. (As aposed to normal install into a partition & using a boot loader)